Lambda Physik Ag

Sartorius-werke Gmbh

Lambda-physik Forschungs-und Entwicklungs Gmbh

Heribert Rosenkranz

Peter Lokai

Franz J Melcher

A control circuit for a pulsed gas laser comprises a plurality of sensors 9, 12, a plurality of control members (e.g. 10) and a central control unit 13. Associated sensors and control members, i.e. sensors which measure a parameter variable by the associated control member, are connected jointly to modules 7, 8, 11 and each module comprises at least one microprocessor; the modules are connected by means of optical waveguides 20 in series in a ring to the central control unit 13. The arrangement makes it possible to save complicated electromagnetic shielding, provides easy fault tracing and simple expansion of the control circuit by further modules.

Control circuit for a pulsed gas laser

For stabilizing the frequency of a narrow-band Excimer laser beam the interference rings of a Fabry-Perot interferometer 16 are projected onto a solid-state image sensor 18 and by means of the solid-state image sensor an electrical signal is generated which is dependent on the frequency of the laser beam. The electrical signal is compared with a stored reference signal to derive an adjusting signal 32 for an optical reflection grating 38 with which the frequency of the laser beam 12 is regulated to a desired value. The absolute value of the frequency of the laser beam 12 is determined by means of the optogalvanic effect.

Method and apparatus for stabilizing the frequency of a laser beam

A calibratable electromagnetically compensating precision balance having a weighing and taring device, in the form of a pan support, is provided with a parallel guide. The output from the balance is fed to an analog-digital converter which has its output coupled, via a minicomputer (calculator), to a display. A reference weight is provided for the balance. The reference weight is externally switchable for its weight determination, i.e., from outside the housing of the balance. A lifting mechanism is provided to lift the pan from the support. A method for compensating the parameters of the above-described calibratable electromechanical balance which can influence sensitivity and accuracy, involves determining and recording the actual value (M) of reference weight, under the prevailing operating conditions using the balance. Forming a quotient from the actual measured value (M) and the set (given) value (m) of the reference weight, the quotient being expressed in the form of a factor (F). Thereafter, multiplying the corresponding measured value of material to be weighed by the correction factor (F) before displaying the value. The correction factor is stored in a memory operatively associated with the minicomputer.

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Gottingen, Germany

Heribert Rosenkranz